The trailer transportation of heavy farm and industrial equipment requires special loading ramps at the rear end of the trailer. For example, FIG. 1 of U.S. Pat. No. 4,372,727 illustrates a typical prior art trailer wherein a hinged ramp or tail is raised or lowered by a pair of hydraulic cylinders. The hydraulic cylinders are pivotally connected to the tail to permit the tail to be lowered into ground engagement so that the heavy equipment nay be moved onto the bed of the trailer. When the equipment has been loaded onto the trailer, the hydraulic cylinders for the tail are extended to raise the tail to a substantially horizontally disposed condition. Normally, the tail will be supporting at least a portion of the equipment positioned on the trailer. Should the hydraulic cylinders for the tail fail, the tail will pivot downwardly relative to the trailer which could cause damage to the equipment being transported and which would constitute a safety hazard as well.
In an effort to prevent the trailer tail from moving downwardly in the case of failure of the hydraulic cylinders or the hydraulic lines connected thereto, separate locking structures have been utilized to prevent the retraction of the tail hydraulic cylinders. However, the separate locking structures are normally quite complex and do substantially increase the cost of manufacturing the trailer.
It is therefore a principal object of the invention to provide a main tail locking device for a hydraulic tail trailer.
A further object of the invention is to provide a main tail lock for a hydraulic tail trailer which is less complex than the prior art devices and which is less expensive to manufacture than the prior art devices.
Yet another object of the invention is to provide a main tail lock for a hydraulic tail trailer which prevents the hydraulic tail from pivoting downwardly should the tail hydraulic cylinders fail.
These and other objects will be apparent to those skilled in the art.